Individual authentication methods can be classified into 3 kinds of authentications, i.e., authentication by knowledge, authentication by belongings, and authentication by biological information. The authentication by knowledge includes, for example, authentication by a password and the authentication by belongings includes, for example, authentication by a magnetic card with a magnetic stripe or an IC card with an IC chip. Also, the authentication by biological information includes authentication by a fingerprint, authentication by a vein, and authentication by an iris.
Also, in the authentication by belongings, there is a method in which a key apparatus including key information performs communication with another external apparatus for authentication. For example, Patent Literature 1 discloses a smart entry system in which a call signal is transmitted from a vehicle side to a key apparatus, and the vehicle side collates a response signal and unlocks a door when the key apparatus replies to the call signal with the response signal including unique ID information.